Switch mechanism



y 1961 c. A. SCHAEFER ET AL 2,982,830

SWITCH MECHANISM Filed May 4, 1959 INVENTOR.

CARL A. SCHAEFER WALTER c. KflECH BY Fig-l United States Patent SWITCHMECHANISM Carl A. Schaefer, Whitefish Bay, and Walter C. Karch,Milwaukee, Wis., assignors to Square D Company, Detroit, Mich, acorporation of Michigan Filed May 4, 1959, Ser. No. 810,786

9 Claims. (Cl. 20083) The invention relates to a pressure sensitiveswitch in which a single electrical switch operating member isresponsive to pressure within a certain range as well as pressures aboveand below that certain range.

In many instances it is necessary to provide signalling systems whichwill signal or indicate when the pressure of fluid or gas in acontainer, for example a pipe line, vehicle tire, tube or the likeincreases, decreases or otherwise deviates from a predetermined desiredpressure. In

many instances, dangerous conditions will exist if the pressure of thefluid or gas within a container deviates from the desired predeterminedpressure. Prior to the present invention various transducers andpressure sensitive switches were used which would respond to a change inpressure to operate a switch or provide a signal. These priortransducers or pressure sensitive switches were designed to operate on achange in pressure in one direction only. For example, the switch wouldbe operated if the pressure in the container increased above a certainpredetermined pressure, or the switch would be designed to operate whenthe pressure decreased below a certain pressure. In these prior designsa single switch would not operate in both directions of changes inpressure. More specifically, it required two switches and two pressuresensing devices to indicate deviations in pressure in both an increasingpressure direction and the decreasing pressure direction.

One of the main objects of the present invention is to overcome theaforementioned problems and to provide a single pressure sensitivedevice having a single switch which is operative by deviation of thepressure in either and both the increasing and decreasing directions.

Another object of the present invention is to provide a pressure sensingdevice which is simple in construction, economical to manufacture andpositive in its operation of operating a switch in response todeviations in pressure in both an increasing pressure direction and adecreasing pressure direction.

Other objects and a fuller understanding of this invention may be had byreferring to the following description and claims, taken in conjunctionwith the accompanying drawings in which:

Figure 1 is a front view illustrating the structure of the invention andwith certain parts in cross section;

Figure 2 is an end view of one end of the structure of Figure 1;

Figure 3 is an end view of the other end of the structure in Figmre 1;and

Figure 4 illustrates a modification of the pushbutton operating levers.

The description, drawings, and claims jointly set forth one or moreembodiments of the present invention and the present contribution to theart of making a pressure sensitive switch for the purpose as herein setforth. As illustrated in the drawings, for the purpose ofexemplification and not of limitation, the invention comprises apressure operated mechanism for depressing push button 11 of a. suitablesnap action switch 12. The snap action switch 12, which may be of anysuitable design commonly on the market, has a push button 11 for causingactuation of the switch upon depressing of the push button in adirection upwardly in Figure 1 and thus towards the center of the switch12. The operating mechanism 10 and the switch 12 are supported incooperative arrangement by a pair of spaced parallel plates 13 and 13.The switch 12 is mounted on the top edges of these plates 13 and 13' andan attacher 14 is provided at one end of the plates for attaching theentire device to a pipe or other similar container which contains fluid,gas or liquid under pressure. Enclosed in and attached around theperiphery thereof to the attacher 14 is a pressure responsive means ordiaphragm 16, one side of which is exposed to the pressure in thecontainer.

The operating mechanism 10 includes a plunger 15 having a head 15'seated against the other side of the pressure responsive means ordiaphragm 16 and biased thereagainst by a biasing spring 17. Attached tothe respective opposite ends of plunger 15 are bell cranks 18 and 19which include switch operating levers 20 and 21, respectively. Theseoperating levers 20 and 21 engage the push button 11 and extend fromtheir respective bell cranks 18 and 19 substantially in a common planetowards each other and parallel to plunger 15 when the pressure in thecontainer and against diaphragm 16 is at a predetermined pressure. Thebell crank 18 is mounted on a pivot 22 extending between parallelelements 13 and 13 and is secured by a pivot pin 23 to the respectiveend of plunger 15. Bell crank 19 is pivoted by a pivot pin 24 toparallel elements 13 and 13' also to plunger 15 by means of a pivot pin25. It is noted that the spring 17, plunger 15, bell cranks 18 and 19,operating levers 20 and 21 and push button 11 are all disposed betweenparallel elements 13 and 13'. In eifect, the plunger 15 and operatinglevers 20 and 21 form opposite sides of a parallelogram, the ends ofwhich are formed by bell cranks 18 and 19.

Referring to Figure 1 it is noted that if the plunger 15 is moved to theright both bell cranks 18 and 19 will be pivoted on their respectivepivot pins 22 and 24, causing operating lever 20* to move downwardly andaway from push button 11, and simultaneously causing operating lever 21to move upwardly to depress push button 11, thereby operating switch 12.On the other hand if plunger 15 moves to the left in Figure 1, bellcranks 18 and 19 will pivot about their respective pivot pins 22 and 24,causing operating lever 21 to move away from push button 11 and causingoperating lever 20 to depress push button 11 and again operate switch12. It is thus apparent that the objects of the invention are met bymovement of the plunger 15 in either direction along the axis of itslength.

Since the plunger 15 extends beyond bell crank 19 and thus externally ofthe parallelogram formed by the plunger, bell cranks and operatinglevers, and is seated against the diaphragm 16, it may be moved in oneof these directions, and in this instance to the right in Figure 1, byexerting pressure against diaphragm 16, and is moved to the left, oropposite direction, by spring 17. The spring 17 exerts pressure in adirection to the left by covering one end of the spring with a plate 26which engages bell crank 19 on the side of plunger 15 opposite pivot pin24. The spring 17 is compressed between the plate 26 and an adjustmentnut 27 mounted on a bolt 28 which extends through spring 17 and is fixedrelative to the suitable pipe attacher 14.

Fine adjustments of the position of operating levers 20 and 21 relativeto plunger 15 may be had by making operating levers 20 and 21 out of aspringable material and providing respective adjustment means 30 and 31,one for each lever. The adjustment means 30 consists of a .nut 32carried by bell crank 18 anda set screw .33 threaded therethrough andabutting against operating lever 20 to adjustably set operating lever 29either closer to or further away from push button 11 when plunger is ina desired position. The adjustment means 31 consists of a nut'34 carriedby bell crank 19 and a .set screw 35 threaded therethrough-and abuttingagainst operating lever 21 to adjustably set operating lever 2!} eithercloser to or further away from .push button 11 when plunger .15 isin thedesired position. In this way both levers 2t) and 21 may besimultaneously abutted against button 11 at any desired pressure settingwherein the pressure against diaphragm 16 positions plunger 15 at acertain position along its axial line of permissible movement.

In Figure 4 a modification of .the operating levers is illustratedwherein each lever extends across push button '11. The end of lever ahas a narrow portion 2% lying alongside a narrow portion 21b on the endof lever 21a. With this construction the levers will exert pressurecloser to the axis of the pushbutton at all positions in their operativemovement and an edge of a lever does not scrape the end of the button 11during operation.

In operation the pressure sensing device is simply installed on apressure line, any other container having fluid under pressure containedtherein in such manner that the pressure in the container operatesthrough pipe attacher 14 against diaphragm :16 to urge diaphragm 16 tothe right in Figure 1. This causes a movement of plunger 15 to the rightuntil a balance is obtained with spring 17 at a desired pressuresetting. Adjustment means 3t] and 31 and adjustment nut 27 are thenadjusted so that the balance condition, wherein operating levers 2th and21 engage, but do not exert pressure, on push button 11 is obtained.When this condition exists the pressure sensing switch is adjusted sothat swicth 12 is in one of its positions, i.e. either open or closed,when the pressure against diaphragm 16 is at the predetermined desiredpressure. If the pressure against diaphragm 16 decreases, spring 17 willcause movement of plunger 15 to the left, and ultimately depression ofpush button 11 by operating lever 26 to operate switch 12. Conversely ifthe pressure against diaphragm 16 increases, diaphragm 16 will pushplunger '15 to the right against spring 17, and cause depression of pushbutton 11 by operating lever 21 to operate switch 12. 'Thus switch 12 isautomatically operated by a pressure different from the desiredpressure, .or when the pressure deviates from the desired pressure.Although this invention has been described in its preferred form with acertain degree of particularity, it is understood that the presentdisclosure of the preferred form has been made only by way of exampleand that numerous changes in the details of construction and thecombination and arrangement of parts may be resorted to withoutdeparting from the spirit and the scope of the invention as hereinafterclaimed.

What is claimed is:

1. In a pressure sensitive switch having an electrical switch providedwith an operating push button, the provision of support means, first andsecond elements operatively carried by said support means and engageablewith the push button for operating the button, a member movable relativeto said support means and coupled to said elements and movable inopposite directions to simultaneously move one of said elements againstsaid button and the other of said elements away from said button, springmeans urging said member in one of said directions, and pressureresponsive means urging said member in the opposite direction andagainst the urging of said spring means.

2. A pressure sensitive device responsive to pressures outside thelimits a preselected pressure range having; an electrical switchprovided with an operating push button, structure supporting saidswitch, the provision of first and second lever means pivoted on saidstructure and engageable with the push button for operating the button 4upon movement of the lever means, a .member operatively coupled to saidlever means and movable in opposite directions to pivotally move saidlever means to simultaneously move one of said lever means against saidbutton and the other of said lever means away from said button, springmeans urging said member in one of said directions, and pressureresponsive means urging said member in the opposite direction andagainst the urging of said spring means, said spring means and saidpressure responsive means being in counterbalance when said pressureresponsive means responds to pressures in said preselected pressurerange and being out of counterbalance when the pressure responsive meansresponds to pressure different from pressures in said preselectedpressure range thereby eiiecting operation or said operating pushbutton.

3. The structure of claim 2 wherein said lever means are in the form ofhell cranks and wherein said members cooperatively are arranged in theform of a parallelogram.

4; The structure of claim 2 wherein said lever means constitute bellcranks and wherein said bell cranks and said member are arranged in theform of a parallelogram, and said member has one end thereof extendingexternally of said parallelogram and seated against said pressureresponsive means, said bell cranks supporting said member for movementaxially by said pressure responsive means and said spring means.

5. The structure of claim 2 wherein said lever means have narrowportions disposed alongside each other and each extending across saidpush button.

6. In-a pressure sensitive switch having an electrical switch providedwith an operating push button, the provision of supporting structuresupporting said switch, a plurality of hell cranks pivoted on saidsupporting structure at spaced locations on opposite sides of said pushbutton, all of said bell cranks having button engageable portionsextending towards each other and engageable with the push button foroperating the button and having member engaging portions, a memberpivotally coupled to said member engaging portions and movable inopposite directions to simultaneously pivot all of hell cranks relativeto said supporting structure to move one of the button engageableportions against the button and simultaneously move the other buttonengageable portions away from the button, spring means urging saidmember in one of said opposite directions, and pressure responsive meansurging said member in the other of said opposite directions and againstthe urging of the spring means, thereby effecting movement of the pushbutton and operation of the switch when the pressure against thepressure responsive means is above or below a predetermined pressure,and thereby to effect release of the push button and release ofoperation of the switch when the pressure against the pressureresponsive means is at a predeter mined pressure wherein said urging ofsaid spring means and pressure sensitive means balance each other.

7. A switch comprising support means, an operating element movable alongsaid support means in a line of movement in one direction, an actuatingmember reciprocally movable along said support means in oppositedirections in a path of movement disposed at an angle to said 'line ofmovement, first means interposed between said member and said elementand operatively carried by said support means to transfer movement ofsaid member in one of said opposite directions to movement of saidelement in said one direction, second means interposed between saidmember and said element and operatively carried by said support means totransfer movement of said member in the other of said oppositedirections to move said element in said one direction.

8. The structure as defined in claim 7 additionally including thefeature wherein said path of movement and said line of movement aretransverse to each other.

9. The structure as defined in claim 9 additionally including thefeature of biasing means biasing said member in one of said oppositedirections and pressure responsive means urging said member in the otherof said opposite directions.

References Cited in the file of this patent UNITED STATES PATENTS CrewSept. 12, 1944 Geisel Sept. 6, 1949 Bordelon Dec. 27, 1949 Grupp Nov.14, 1950 Spracher Sept. 18, 1956 Mercier Apr. 16, 1957 UNITED STATESPATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 2,982,830 May 2, 1961Carl A. Sch aefer et al.

It is hereby certified that error appears in the above numbered pat--ent requiring correction and that the said Letters Patent should read ascorrected below.

Column 4, line 73,

for the claim reference numeral "9" read 7 Signed and sealed this 14thday of November 1961.

(SEAL) Attest:

ERNEST W. SWIDER Attesting Officer DAVID L. LADD Commissioner of PatentsUSCOMM-DC UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION v PatentNo, 2,982,830 May 2, 1961 Carl A. Schaefer et a1.

It is hereby certified that error appears in the above numbered patentrequiring correction and that the said Letters Patent should read ascorrected below.-

Column 4, line 73, for the claim reference numeral "9" read 7 Signed andsealed this 14th day of November 1961.

(SEAL) Attest:

ERNEST W. SWIDER DAVID L. LADD Attesting Officer I Commissioner ofPatents USCOMM-DC

